1. Field of the Invention
The present invention pertains to a method and apparatus for the treatment of organic wastes and other materials in sewers and other waste-laden environments. More particularly, the present invention pertains to a method and apparatus for continuous in-situ microbial seeding in sewers and other waste-laden environments for treatment of organic wastes and other similar materials.
2. Description of the Related Art
Water treatment facilities in general, and sewer systems in particular, are frequently confronted with a number of different problems. One especially prevalent problem is the emission of unpleasant odors. Such odors, which can frequently spread to surrounding areas, can emanate from a number of different sources. While these odors often come directly from waste materials contained within sewers and other facilities, unpleasant odors are also frequently caused by toxic and/or malodorous substances such as hydrogen sulfide which are produced when anaerobic, sulfide-producing microbial populations are allowed to flourish within a particular environment. Odor emission can be particularly problematic when a sewer or other facility in question is located in or near an inhabited area.
In addition to odor emissions, another problem facing sewer systems and water treatment facilities is corrosion. In many cases, such corrosion can be caused by unwanted microbial populations. For example, hydrogen sulfide and other microbial by-products can be extremely corrosive and damaging to pipes, drains, basins and other components of sewer systems and/or water treatment facilities. Further, because such equipment is frequently located underground, it can often be very expensive, difficult and time consuming to replace.
Yet another problem routinely faced by sewer systems and other water treatment facilities is the handling of grease, oil and similar organic matter. Devices known as “grease traps” are required on virtually all commercial facilities that discard liquid or solid grease into sewer systems. Nonetheless, grease, oil and other related organic materials inevitably still find their way into sewer systems and, eventually, water treatment plants. Grease, oil and related substances can plug pipes and other equipment. When this occurs, maintenance crews most often pump out the blockage or, in extreme cases, dig up the pipes and/or other equipment in order to physically remove the obstructions. Moreover, present sewer and/or water treatment facilities are frequently unable to process increased volumes of organic matter without significant capital investment in new equipment.
In many conventional sewer systems, wet-wells are frequently utilized to transport the sewage to a higher elevation. These wet well locations act as a collection point for grease, oils and other organic matter that is not decomposed within the water flow. As a result, it is a common necessity to clean out the wet wells at pumping stations or other junction points in the system where floating grease and organic matter collects, hardens and remains until it is physically removed. Sewer lines with low flow rates, bends, and/or changes in elevation are also prone to build up of organic deposits.
Throughout the specification and claims reference is made to “treatment of wastes in sewers and other facilities”. This phrase and other similar terminology, is intended to be broad and to include sewage collection systems, as well as other similar environments. For example, this invention is effective in sewer wet wells. However, the invention is also effective in other applications such as grease traps which are purposely maintained in a parallel relationship to standard waste water collection systems.
It is well known that certain microbes can be used in the prevention and/or treatment of the aforementioned problems. Such microbes can naturally mineralize or break down organic matter into harmless elements, such as carbon dioxide and water. As such, it has been found that certain microbes can be used to beneficially control or eliminate malodorous and/or toxic effluents in sewer wet-wells and other treatment facilities. Microbes can also be used to mineralize grease, oil and similar organic substances in such environments.
A common approach to microbial treatment of wastes in sewers and other facilities has been the use of “dosing stations” wherein one or more desired microbial populations are grown, and then subsequently added to the specific environment to be treated. Such microbial populations are added to the environment to be treated in periodic doses. In some cases, the microbial populations are grown at remote locations and then transported to the sewer or other facility to be treated. In other instances, microbial populations are grown near the sewer or other facility to be treated and then added to such sewer or other facility.
Unfortunately, periodic dosing of microbial agents for the treatment of wastes in sewers and other facilities has yielded results which are less than satisfactory. Competition for resources, lack of nutrients and natural enemies can combine to inhibit rapid growth of beneficial microbial agents. Thus, unless proper growth and delivery of microbial agents is employed, the beneficial microbes will not be effective where the breakdown of organic materials is desired. Put another way, simply dumping microbes into a particular environment to be treated seldom provides the desired results.
One major limitation associated with the periodic dosing of microbial populations for waste remediation purposes is the fact that there is no way to continuously monitor and/or control the amount of microbes to be added to a particular environment being treated. As a result, microbes must be added on an essentially arbitrary schedule, without regard for the specific amount of microbial population required to optimize the waste remediation process. Accordingly, there is no way to determine whether microbial agents have been fully spent and, therefore, whether additional microbes are needed to optimize waste treatment benefits.
The limitations associated with periodic dosing or addition of microbial populations to waste-laden environments become very apparent in the case of system “upsets.” Such upsets occur when unexpected slugs of concentrated wastes or highly toxic substances are introduced into an environment which is being treated with microbial agents. In such instances, beneficial microbial populations can frequently become overwhelmed, and the mineralization process essentially stalls. When this occurs, the waste remediation process essentially shuts down. Moreover, the waste treatment process cannot begin again until a new and sufficiently robust dose of beneficial microbes is added to the waste stream.
A number of patents describe methods and devices for using microbes to treat organic wastes in sewers and other similar environments. Several of these patents disclose inventions which use containers that can be immersed or submerged directly into the waste-laden environments to be treated. Examples of such patents include U.S. Pat. No. 4,670,149 to Francis; U.S. Pat. No. 4,810,385 to Hater, et al.; U.S. Pat. No. 4,925,564 to Francis; U.S. Pat. No. 5,516,687 to Perez, et al., U.S. Pat. No. 5,911,877 to Perez, et al.; U.S. Pat. No. 5,879,932 to Van Erdewyk, et al.; U.S. Pat. No. 5,935,843 to Glendening, et al.; and U.S. Pat. No. 6,248,234 to Cline. However, unlike the invention described herein, the devices described in the aforementioned patents still require periodic addition (i.e., “dosing”) of microbial cultures into the environment to be treated.
U.S. Pat. No. 5,314,620 to Staniec describes a method and apparatus for the use of microbes to purify cutting oil, such as used in metal machining equipment. The '620 patent describes means for aerating such cutting oil to encourage growth of aerobic bacteria, and to discourage the growth of unwanted anaerobic bacteria. However, the method and apparatus described in the '620 patent do not provide for direct aeration of the beneficial microbial populations, or the addition of nutrients directly to said microbial populations. Furthermore, because cutting oil is kept in a relatively small reservoir, the method and apparatus described in the '620 patent does not promote beneficial microbial spreading throughout larger environments.
U.S. Pat. No. 4,994,391 discloses a system utilized to produce active bacteria to breakdown chemical or biological wastes in waste water effluents. The system described in the '391 patent utilizes a combination of a culturing basin and an acclimator basin in a temperature controlled space. The culturing basin contains numerous components, such as a series of removable nutrient suspension means and a vertical collection pipe with holes. The bacteria are cultured in the presence of the nutrient suspension means as bacteria are pumped out of one or two of these culturing basins into the acclimator basin. The system disclosed in the '391 patent is significantly more complicated and expensive to use than the present invention.
Thus, there is a need for an inexpensive way to continuously add desired microbial populations to sewers and other similar environments so that such microbial populations can beneficially attack organic materials for waste remediation purposes, yet avoiding limitations associated with simple dosing of microbial agents. Further, the system used to continuously add such microbial populations should be able to handle unexpected or periodic slugs of concentrated wastes or other highly toxic substances without experiencing a system upset or other prolonged treatment disruption.